FIG. 1 shows a perspective view of an example automotive instrument panel of the prior art. FIG. 2 shows a side, cut away view of the instrument panel of FIG. 1. As shown in FIG. 1, instrument panel 100 consists of a housing 105 having a generally triangular cross section, as shown in FIG. 2. As shown in FIG. 1, housing 105 has opaque top, back, and right, and left sides 115, 110, 117 and 116, respectively, and a transparent front panel 120. Instruments such as a speedometer 150 and tachometer 155 and other indicators such as a clock, temperature, oil pressure, and fuel gauges are typically mounted to back side 110. The faces of these instruments are typically supplied with measurement marks and numbers in white or another bright color that stands out against the background of back side 110, which is typically black. As shown in FIG. 2, the housings 200 of instruments such as speedometer 150 and tachometer 155 typically extend outwards from back side 110 of instrument panel 100.
The faces of the dashboard instruments are typically illuminated by one or more illumination units. In the embodiment of FIG. 1, two illumination units 122 and 124, respectively, are used. Multi-colored illumination unit 122 includes a translucent light diffusing panel 125 and a light source 130. Similarly, illumination unit 124 includes a diffusing panel 135 and a light source 140. Light sources 130 and 140 are typically 12 volt electric light bulbs that produce white light. Diffusing panels 125 and 135 are typically pieces of translucent plastic. Diffusing panels 125 and 135 are both the same color. The most common colors are white, reddish-orange, and green. The purpose of diffusing panels 125 and 135 are to disperse the light of bulbs 130 and 140, respectively, so as to provide even lighting of the instrument faces on back side 110. As shown in FIG. 2, light from each bulb is dispersed by its respective diffusing panel, reflects off transparent front panel 120, and illuminates back side 110.
In the prior art, the intensity of dashboard instrument illumination is variable, but the color is fixed. The intensity may be adjusted by a driver by adjusting the intensity of the light emitted by the light sources, typically using a variable resistance control. The color of the illuminated instrument faces is determined by the color of the markings on the face of the instruments and the color of the diffusing panels. For example, if the instrument markings are white, the markings when illuminated appear to be the same color as that of the diffusing panels. If white diffusing panels are used, the instrument markings appear white. If orange diffusing panels are used, the instrument markings appear orange. If green diffusing panels are used, the instrument markings appear green.
Up until now, the color of dashboard instrument illumination available in a particular car is fixed and determined by the car manufacturer, even though a purchaser or driver of a vehicle may prefer a different color from the color implemented by the manufacturer. There is a need for a system that allows a driver to select a desired instrument illumination color.